Just before two o’clock in the morning, the President of COP-20, Manuel Pulgar Vidal, Peru’s Minister of Environment, gaveled the approval of the text, without dissent. At that moment, the foundation was established for the next major international climate agreement, which – under the auspices of the Durban Platform for Enhanced Action – will be finalized and signed one year from now at COP-21 in Paris, France, for implementation in 2020.

After five days on the ground in Lima, where I participated in a variety of events and met with a diverse set of national negotiating teams, I’ve reviewed the agreed text of the Lima Call for Climate Action (which I abbreviate below as the “Lima decision”), and can now reflect on its gestation, its meaning, and its implications.

The Lima Call for Climate Action

By establishing a new structure in which all countries will state (over the next six months) their contributions to emissions mitigation, this latest climate accord moves the process in a productive direction in which all nations will contribute to the reduction of greenhouse gas emissions.

Working to fulfill the promise made in the 2011 Durban Platform for Enhanced Action to include all parties (countries) under a common legal framework, the Lima decision constitutes a significant departure from the past two decades of international climate policy, which – since the 1995 Berlin Mandate and the 1997 Kyoto Protocol – have featured coverage of only a small subset of countries, namely the so-called Annex I countries (more or less the industrialized nations, as of twenty years ago).

The expanded geographic scope of the Lima Call for Climate Action and thereby the incipient Paris agreement – and the emerging architecture of a pragmatic hybrid combining bottom-up “Intended Nationally Determined Contributions” (INDCs) with top-down elements for reporting and synthesis of contributions by the UNFCCC Secretariat – represents the best promise in many years of a future international climate agreement that is truly meaningful.

Importantly, the Lima decision provides that each country’s INDC shall include a clear statement of emissions mitigation, and may include quantifiable information on reference points (such as base year), time frame of implementation and coverage, assumptions and methodological approaches for estimating and accounting for greenhouse gas emissions, as well as each country’s own assessment of its INDC’s fairness and ambition. These statements of national contributions are to be submitted by the end of March, 2015, although countries that miss that “deadline” can then make their submissions by June.

Compromises, Compromises

Because of the ongoing sharp divide in climate talks between developed and developing countries, the Lima decision was difficult to accomplish and could only be achieved through compromises that had the effect of watering down various aspects of the accord. This suggests that the road to Paris may be difficult for the negotiators.

The substitution of the phrase “may include” for “shall include” in regard to the elements of the INDCs was one of the compromises that was necessary to gain the approval of developing countries. So, the U.S.-favored requirement for the use of transparent elements in INDCs that would facilitate comparisons among countries was dropped.

However, at least one negotiating team with whom I met in Lima maintained that the analyses and comparisons of INDCs that will inevitably be carried out by various NGOs and research organizations (including universities) will provide the needed transparency and therefore the needed encouragement to countries for greater ambition.

A review period for the INDCs, favored by the countries most vulnerable to climate change (sub-Saharan Africa and the small island states), was also scrapped. Instead, a synthesis report will be prepared by the UNFCCC Secretariat by November 1st, 2015 (based on INDCs submitted by October 1st).

The delegates from the vast majority of countries were well aware of the fact that the announced China-USA INDCs move the world from the 14% of global CO2 emissions covered by nations participating (a subset of the Annex I countries) in the Kyoto Protocol’s current commitment period to a future Paris agreement that now covers more than 50% of global CO2 emissions, with Europe already on board.

Under the decision text of the Lima Call for Climate Action, within the next six months the other industrialized countries will announce their own contributions, and — more importantly – so will the other large, emerging economies – India, Brazil, Korea, South Africa, Mexico, and Indonesia. Coverage of 80% to 90% of global emissions can be anticipated, although major questions remain regarding what can be expected from some key countries, including India, Russia, and Australia.

Broad, Then Deep

In a 1998 book, edited by Bill Nordhaus (Economics and Policy Issues in Climate Change), Dick Schmalensee wrote about “Greenhouse Policy Architectures and Institutions,” and lamented that the Kyoto Protocol exhibited narrow scope (covering only the Annex I countries) but aggressive ambition for that small set of nations. He presciently noted that this was precisely the opposite of what would be a sensible way forward, namely broad participation, even if the initial ambition is less. Based on the 2011 Durban Platform and the 2014 Lima Call for Climate Action, it now appears that with the 2015 Paris Agreement that approach is finally being adopted.

As I said in my previous essay, these well-intentioned advocates mistakenly focus on the short-term change in emissions among participating countries (for example, the much-heralded 5.2% cut by the Annex I countries in the Kyoto Protocol’s first commitment period), when it is the long-term change in global emissions that matters.

They ignore the geographic scope of participation, and do not recognize that — given the stock nature of the problem — what is most important is long-term action. Each agreement is no more than one step to be followed by others. And most important now for ultimate success later is a sound foundation, which is what the Lima decision can provide.

Major Challenges Along the Road to Paris

The major sticking points from now until the Paris talks, where it is hoped that the new post-2020 agreement will be signed, are all associated with the divide between rich and poor nations.

The ongoing talks will need to satisfy the interests of both the rich and the poor countries in regard to finance mechanisms, including the realization of the $100 billion commitment that was made in Copenhagen.

Also, looming in the wings is the loss and damage mechanism created in the Warsaw talks last year to help the most vulnerable nations cope with the effects of climate change. Island nations want that mechanism to become another stream of funding from the rich countries, but the rich countries are concerned that the mechanism might lead to some notion of legal liability (and thereby a blank check). The loss and damage concept was reiterated (but not expanded) in the Lima decision.

These and other pending issues mean that the upcoming talks in 2015 in Geneva and Bonn, prior to the December 2015 Paris Conference, will continue to require difficult negotiations across the divide between rich and poor countries.

Difficult indeed. Whereas the agreed decision text from Lima (the “Lima Call for Climate Action”) is less than four pages in length, the Annex (“Elements for a Draft Negotiating Text”) of additional options for the Paris Agreement extends to more than 37 pages!

The Bottom Line

Although it is true that the Lima decision text was watered down in the last 30 hours (as a result of very effective opposition by developing countries), the fact remains that a new way forward has been established in which all countries participate and which therefore holds promise of meaningful global action to address the threat of climate change. So, despite all the acrimony among parties and the 30-hour delay in completing the talks, the negotiations in Lima these past two weeks may turn out to be a key step along the way.

The Nineteenth Conference of the Parties (COP-19) of the United Nations Framework Convention on Climate Change (UNFCCC) came to a close in Warsaw, Poland, on Saturday, November 23rd, after what has become the norm – several all-night sessions culminating in last-minute negotiations that featured diplomatic haggling over subtle changes to the text on which countries were finally willing to agree. The key task of this COP was essentially to pave the way for the negotiations next year at COP-20 in Lima, Peru, as a lead-up to the real target, reaching a new international climate agreement at the 2015 negotiations in Paris to be implemented in 2020, when the second commitment period of the Kyoto Protocol comes to an end. If that was the key objective, then the Warsaw meetings must be judged to be at least a modest success – the baton was not dropped, rather it was passed successfully in this long relay race of negotiations.

Before going further, I would like to acknowledge something else about COP-19 in Warsaw, namely the excellent logistics. Anyone who suffered through the disastrous logistical arrangements for COP-15 in Copenhagen will not take this for granted. Perhaps ironically, in the years I’ve been participating in these annual events, the two best organized conferences (in terms of logistical arrangements) were the two Polish COPs – COP-14 in Poznan in 2008 and COP-19 in Warsaw this year.

As I have written in many previous essays at this blog, the challenges standing in the way of an effective international climate change agreement are numerous and severe. A brief historical account is necessary to explain the significance of what transpired in Warsaw. However, if you’re familiar with international climate policy, particularly the history of these international negotiations, I suggest you skip the next section and move directly to “Issue #1: Making Progress toward a Post-Kyoto Agreement.”

Some Historical Background to Place the Warsaw Talks in Context: the UNFCCC, the Berlin Mandate, the Kyoto Protocol, and the Durban Platform

The U.N. Framework Convention on Climate Change, adopted at the U.N. Conference on Environment and Development (the first “Earth Summit”) in Rio de Janeiro, Brazil, in 1992, contains what was to become a crucial passage: “The Parties should protect the climate system for the benefit of present and future generations of humankind, on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. Accordingly, the developed country Parties should take the lead in combating climate change and the adverse effects thereof.” [emphasis added] The countries considered to be “developed country Parties” were listed in an appendix to the 1992 Convention ­– Annex I.

The phrase – common but differentiated responsibilities – was given a specific interpretation three years after the Earth Summit by the first decision adopted by the first Conference of the Parties (COP-1) of the U.N. Framework Convention, in Berlin, Germany, April 7, 1995 ­­– the all important Berlin Mandate, which interpreted the principle as: (1) launching a process to commit (by 1997) the Annex I countries to quantified greenhouse gas emissions reductions within specified time periods (targets and timetables); and (2) stating unambiguously that the process should “not introduce any new commitments for Parties not included in Annex I.”

Thus, the Berlin Mandate established the dichotomous distinction whereby the Annex I countries were to take on emissions-reductions responsibilities, and the non-Annex I countries were to have no such responsibilities whatsoever. This had wide-ranging and profound consequences, because it became the anchor that prevented real progress in international climate negotiations. With 50 non-Annex I countries coming to have greater per capita income than the poorest of the Annex I countries, the distinction was out of whack within a few years.

But, more important than that, this dichotomous distinction meant that: (a) half of global emissions would be from nations without constraints; (b) the world’s largest emitter – China – would be unconstrained; (c) aggregate compliance costs would be driven up to be four times their cost-effective level, because many opportunities for low-cost emissions abatement in emerging economies were taken off the table; and (d) an institutional structure was perpetuated that made change and progress virtually impossible.

The dichotomous Annex I/non-Annex I distinction remained a central – indeed, the central – feature of international climate negotiations from COP-1 in Berlin in 1995 continuously until COP-15 in 2009, when hints of possible change first appeared. The Copenhagen Accord (2009) and the Cancun Agreements (2010) began a process of blurring the Annex I/non-Annex I distinction. But this blurring was only in the context of the interim pledge-and-review system established at COP-15 in Copenhagen and certified at COP-16 in Cancun, not in the context of an eventual successor to the Kyoto Protocol. Thus, the Berlin Mandate retained its centrality.

Rather than adopting the Annex I/non-Annex I (or industrialized/developing country) distinction, the Durban Platform focuses instead on the pledge to create a system of greenhouse gas reductions including all Parties (what matters, really, is all key countries) by 2015 that will come into force by 2020. Nowhere in the text of the decision were phrases such as “Annex I,” “common but differentiated responsibilities,” “distributional equity,” “historical responsibility,” all of which had long since become code words for targets for the richest countries and blank checks for all others.

By replacing the Berlin Mandate, the Durban Platform opened an important window. National delegations from around the world took on the challenging task to identify a new international climate policy architecture that is consistent with the process, pathway, and principles laid out in the Durban Platform, namely to find a way to include all (key) countries (such as the 20 largest national and regional economies that together account for upwards of 80% of global carbon dioxide emissions) in a structure that brings about meaningful emissions reductions within an appropriate timetable at acceptable cost, while remaining within the overall framework provided by the UNFCCC, including the celebrated principle of common but differentiated responsibilities.

Issue #1: Making Progress toward a Post-Kyoto Agreement

In Warsaw, the negotiators were tasked under the Durban Platform track (the so-called “ADP” track) to develop a work plan of substantive topics and a related calendar that will lead to the development of the text of an agreement of a new comprehensive policy architecture that can be discussed at COP-20 in Lima one year from now and then subject to final consideration and adoption a year after that at COP-21 in Paris. This they did, and in the process they identified six components for the new architecture: mitigation, adaptation, finance, technology development and transfer, capacity-building, and transparency of action and support. Some of these are more necessary than others, but it was this package that generated agreement in Warsaw.

The actual agreement in Warsaw could only be achieved through carefully negotiated text. The delegates’ obligation is to eventually adopt “a protocol, another legal instrument or an agreed outcome with legal force under the Convention applicable to all Parties…” In truth, the phrase “under the Convention” is not necessary, because any decision by the UNFCCC is under the Convention, and therefore it is the case that any agreement produced under the Durban Platform is still subject to the UNFCCC principle of “common but differentiated responsibilities.” But the large emerging economies tend to view the phrase “under the Convention” as supporting the dichotomous distinction of, on the one hand, commitments for Annex I (industrialized) countries to reduce emissions, and, on the other hand, no obligations for non-Annex I (developing) countries, who would take actions only voluntarily and only with financial assistance from the Annex I countries. The same set of large emerging economies insisted that if they were to be included in the agreement, then the word “commitments” must be replaced by “contributions.”

As I predicted at the conclusion of last year’s climate negotiations (COP-18) in Doha, Qatar, the issue that held the greatest potential for blowing up this year’s talks in Warsaw was the topic of “loss and damage,” which the delegates agreed to put on the agenda for discussion this year at COP-19. The phrase “loss and damage” is typically understood to refer to the range of damages and loss associated with climate change impacts in developing countries that are particularly vulnerable to the adverse effects of climate change. Discussions about potential international policy in this realm frequently bring up thoughts about who should pay for such loss and damages, presumably those most responsible for climate change.

Since climate change is a function not of current emissions, but of concentrations, responsibility for damages is presumably correlated with cumulative emissions. Hence, the industrialized countries, in particular, the United States, worry that negotiations on “loss and damage” would soon raise the specter of unlimited legal liability.

The link is less direct than one might think, however. First, there is the global commons nature of the problem, meaning that climate change cannot be linked to emissions from a specific country. Second, there is the highly stochastic link from climate change to changes in weather patterns, so that no specific weather incident – whether Superstorm Sandy in New York, Hurricane Katrina in New Orleans, or Typhoon Haiyan in the Philippines – can be deterministically linked with global climate change. These two scientific realities mean that moving from “loss and damage” to legal liability would be a long and perilous road.

But this is a very important issue in the climate negotiations for many developing countries, in particular, for the small island states that are most at risk. Hence, it should not be surprising that this area of discussion – in some ways only a sideshow of the primary talks on reducing emissions and the risk of climate change – almost caused the talks to collapse.

In the end, the delegates agreed to finesse the topic by creating the Warsaw International Mechanism for Loss and Damage, which does not mention liability or promise compensation, but rather states that this is a topic to be discussed further at future meetings, and under the general topic of adaptation to climate change.

Issue #3: Finance

Those are two – the Durban Platform, and Loss and Damage – of three major issues that were considered in Warsaw. The third was “finance,” that is, the question of when and how the industrialized countries will meet the commitment they made at COP-15 in Copenhagen in 2009 to begin delivering $100 billion per year of financial assistance to developing countries in 2020 to help with mitigation and adaptation. Not surprisingly, there was little or no progress on that front. More about this in a future essay. For now ….

The Path Ahead – Any Reason for Optimism?

Given my description above of the debates and “resolution” regarding the major issues, is there any cause for optimism regarding the path ahead. Regular readers of this blog will know that I tend to see the half-full glass (or one-tenth full glass) of water, and in this case I think there really is cause for cautious optimism regarding the path ahead.

This is based upon a singular reality – the growing convergence of interests between the two most important countries in the world when it comes to climate change and international policy to address it, namely, China and the United States.

First of all, the annual carbon dioxide (CO2) and greenhouse gas (GHG) emissions of these two countries have already converged. Whereas U.S. CO2 emissions in 1990 were almost twice the level of Chinese emissions, by 2006 China had overtaken the United States. We are the world’s two largest emitters.

Second, as I explained above, cumulative emissions are particularly important, because they are what cause climate change. Any discussion of distributional equity in the climate realm inevitably turns to considerations of historic responsibility. Looking at the period 1850-2010, the United States led the pack, accounting for nearly 19% of cumulative global emissions of GHGs, with the European Union in second place with 17%, and China third, accounting for about 12% of global cumulative emissions. But that is changing rapidly, because of the fact that emissions are flat to declining throughout the industrialized world, but increasingly rapidly in the large emerging economies, in particular, China. Depending upon the relative rates of economic growth of China and the United States, as well as many other factors, China may top all countries in cumulative emissions within 10 to 20 years from now.

Third, China and the United States both have historically high reliance on coal for generating electricity. At a time at which U.S. dependence on coal is decreasing (due to increased supplies of unconventional natural gas and hence lower gas prices ), China continues to rely on coal, but is very concerned about this, partly because of localized health impacts of particulates and other pollutants. Importantly, both countries have very large shale gas reserves. U.S. output (and use for electricity generation) has been increasing rapidly, bringing down CO2 emissions, whereas Chinese exploitation and output has been constrained by available infrastructure (i.e., lack of pipelines, but that will change).

Fourth, in both countries, sub-national climate policies – cap-and-trade systems – are moving forward. In the case of the China, seven pilot CO2 cap-and-trade regimes at the local level are under development, while in the United States, California’s ambitious AB-32 cap-and-trade system continues to make progress.

There was no fundamental setback in Warsaw to the stream of work that needs to be accomplished in Lima in 2014 in preparation for an agreement to be reached in Paris in 2015 under the Durban Platform for Enhanced Action. This, combined with the reality of increasing convergence of Chinese and U.S. perspectives and interests, leaves me cautiously optimistic (or perhaps, just hopeful) about the path ahead.

Given all the excitement, let’s first take a look at the transcript of what the President actually said on this topic:

We will respond to the threat of climate change, knowing that the failure to do so would betray our children and future generations. Some may still deny the overwhelming judgment of science, but none can avoid the devastating impact of raging fires, and crippling drought, and more powerful storms. The path towards sustainable energy sources will be long and sometimes difficult. But American cannot resist this transition. We must lead it. We cannot cede to other nations the technology that will power new jobs and new industries. We must claim its promise. That’s how we will maintain our economic vitality and our national treasure, our forests and waterways, our crop lands and snow capped peaks. That is how we will preserve our planet, commanded to our care by God.

President Obama’s second term in office began on Inauguration Day, January 21st, and the list of policy challenges facing his administration is daunting. Aside from the difficult task of addressing the nation’s economic woes, the president and his administration will also deal with the increasing complexities of global climate change, a rapidly changing energy market, entitlement and tax reform, healthcare reform, and the repercussions from the still simmering “Arab Spring.” Throughout this month, we will solicit the viewpoints of a variety of HKS faculty members to provide a range of perspectives on the promise and pitfalls of The Second Term.

We spoke with Robert Stavins, Albert Pratt Professor of Business and Government, and Director of the Harvard Environmental Economics Program, about energy and environmental policy issues the president will face in the next four years.

Q: What are the top priorities for a second Obama administration in energy and environmental policy?

A: The Obama administration faces a number of impending challenges in the energy and environmental policy realm in its second term, which I would characterize – in very general terms – as finding balance among three competing factors: (1) demands from some constituencies for more aggressive environmental policies; (2) demands from other constituencies – principally in the Congress – for progress on so-called “energy security;” and (3) recognition that nothing meaningful is likely to happen if the country’s economic problems are not addressed.

Q: What will be the potential challenges/roadblocks in the way of implementing those top priorities?

The numbers are dramatic. For example, when the Clean Air Act Amendments of 1990 that established the landmark SO2 allowance trading system were being considered in the U.S. Congress, political support was not divided on partisan lines. Indeed, environmental and energy debates from the 1970s through much of the 1990s typically broke along geographic lines, rather than partisan lines, with key parameters being degree of urbanization and reliance on specific fuel types, such as coal versus natural gas. The Clean Air Act Amendments of 1990 passed the U.S. Senate by a vote of 89-11 with 87 percent of Republican members and 91 percent of Democrats voting yea, and the legislation passed the House of Representatives by a vote of 401-21 with 87 percent of Republicans and 96 percent of Democrats voting in support.

But, 20 years later when climate change legislation was receiving serious consideration in Washington, environmental politics had changed dramatically, with Congressional support for environmental legislation coming mainly to reflect partisan divisions. In 2009, the U.S. House of Representatives passed the American Clean Energy and Security Act of 2009 (H.R. 2454), often known as the Waxman-Markey bill, that included an economy-wide cap-and-trade system to cut carbon dioxide (CO2) emissions. The Waxman-Markey bill passed by a narrow margin of 219-212, with support from 83 percent of Democrats, but only 4 percent of Republicans. (In July 2010, the U.S. Senate abandoned its attempt to pass companion legislation.) Political polarization in the Congress (and the country) has implications far beyond energy and environmental policy, but it is particularly striking in this realm.

Q: In the Obama administration’s second term, are there openings/possibilities for compromises in those areas?

A: It is conceivable – but in my view, unlikely – that there may be an opening for implicit (not explicit) “climate policy” through a carbon tax. At a minimum, we should ask whether the defeat of cap-and-trade in the U.S. Congress, the virtual unwillingness over the past 18 months of the Obama White House to utter the phrase “cap-and-trade” in public, and the defeat of Republican Presidential candidate Mitt Romney indicate that there is a new opening for serious consideration of a carbon-tax approach to meaningful CO2 emissions reductions in the United States.

Clearly, this “opening” is being embraced with enthusiasm in the policy wonk world. But what about in the real political world? The good news is that a carbon tax is not “cap-and-trade.” That presumably helps with the political messaging! But if conservatives were able to tarnish cap-and-trade as “cap-and-tax,” it surely will be considerably easier to label a tax – as a tax! Also, note that President Obama’s silence extends beyond disdain for cap-and-trade per se. Rather, it covers all carbon-pricing regimes.

So as a possible new front in the climate policy wars, I remain very skeptical that an explicit carbon tax proposal will gain favor in Washington. Note that the only election outcome that could have lead to an aggressive and successful move to a meaningful nationwide carbon pricing regime would have been: the Democrats took back control of the House of Representatives, the Democrats achieved a 60+ vote margin in the Senate, and the President was reelected. Only the last of these happened. It’s not enough.

A more promising possibility – though still unlikely – is that if Republicans and Democrats join to cooperate with the Obama White House to work constructively to address the short-term and long-term budgetary deficits the U.S. government faces, and if as part of this they decide to include not only cuts in government expenditures, but also some significant “revenue enhancements” (the t-word is not allowed), and if (I know, this is getting to be a lot of “ifs”) it turns out to be easier politically to eschew increases in taxes on labor and investment and turn to taxes on consumption, then there could be a political opening for new energy taxes, even a carbon tax.

Such a carbon tax – if intended to help alleviate budget deficits – could not be the economist’s favorite, a revenue-neutral tax swap of cutting distortionary taxes in exchange for implementing a carbon tax. Rather, as a revenue-raising mechanism – like the Obama administration’s February 2009 budget for a 100%-auction of allowances in a cap-and-trade scheme – it would be a new tax, pure and simple. Those who recall the 1993 failure of the Clinton administration’s BTU-tax proposal – with a less polarized and more cooperative Congress than today’s – will not be optimistic.

Nor is it clear that a carbon tax would enjoy more support in budget talks than a value added tax (VAT) or a Federal sales tax. The key question is whether the phrases “climate policy” and “carbon tax” are likely to expand or narrow the coalition of support for an already tough budgetary reconciliation measure. The key group to bring on board will presumably be conservative Republicans, and it is difficult to picture them being more willing to break their Grover Norquist pledges because it’s for a carbon tax.

Combined with that is Assembly Bill 32 (AB 32) in the state of California, which includes a CO2 cap-and-trade system that is more ambitious in percentage terms than Waxman-Markey was in the U.S. Congress, and which became binding on January 1, 2013. Add to that the recent economic recession, which reduced emissions. And more important than any of those are the effects of developing new, unconventional sources of natural gas in the United States on the supply, price, and price trajectory of natural gas, and the consequent dramatic movement that has occurred from coal to natural gas for generating electricity. In other words, there will be actions having significant implications for climate, but most will not be called “climate policy,” and all will be within the regulatory and executive order domain, not new legislation.

Q: Are there lessons that a second Obama administration can draw upon from the first administration, or from history, when constructing its energy & environmental policy over the next four years?

A: It will take a great deal of dedicated effort and profound luck to find political openings that can bridge the wide partisan divide that exists on climate change policy and other environmental issues. Think about the following. Nearly all our major environmental laws were passed in the wake of highly publicized environmental events or “disasters,” including the spontaneous combustion of the Cuyahoga River in Cleveland, Ohio, in 1969, and the discovery of toxic substances at Love Canal in Niagara Falls, New York, in the mid-1970s. But note that the day after the Cuyahoga River caught on fire, no article in The Cleveland Plain Dealer commented that the cause was uncertain, that rivers periodically catch on fire from natural causes. On the contrary, it was immediately apparent that the cause was waste dumped into the river by adjacent industries. A direct consequence of the observed “disaster” was, of course, the Clean Water Act of 1972.

But climate change is distinctly different. Unlike the environmental threats addressed successfully in past U.S. legislation, climate change is essentially unobservable to the general population. We observe the weather, not the climate. Notwithstanding last year’s experience with Super Storm Sandy, it remains true that until there is an obvious, sudden, and perhaps cataclysmic event – such as a loss of part of the Antarctic ice sheet leading to a dramatic sea-level rise – it is unlikely that public opinion in the United States will provide the tremendous bottom-up demand that inspired previous congressional action on the environment over the past forty years.

That need not mean that there can be no truly meaningful, economy-wide climate policy (such as carbon-pricing) until disaster has struck. But it does mean that bottom-up popular demand may not come in time, and that instead what will be required is inspired leadership at the highest level that can somehow bridge the debilitating partisan political divide.